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Is the expected function so secret that you can't explain?And additionally the function is not obvious.
Hi,
From post#2:
Is the expected function so secret that you can't explain?
Klaus
I would be inclined to think that this is an overvoltage
warning light and if true, then I would pick a PNP BJT
for the function with emitter to the LT1057, base to
the resistor/zener/resistor and collector to the DG408 /
bulb leg. Then when emitter goes above base by 0.7V
you light the bulb, and the zener can be picked for a
roughly-right fault threshold.
Why the DG408 is there at all, is a mystery (maybe a
secondary defeat / enable to the crude comparison).
Really shorted or low resistance? Could be a JFET and not defective.
There are many annoying points with this thread
- cross posting an old question without at least referring to the previous thread
- not giving appropriate information, e.g. the TO92 photo, from the start. Your pin numbers are confused, unfortunately.
The pin assignment matches popular PJFETs like J174, it could be a lower ohmic switch JFET variant. Can be easily verified by identifying the gate diode junction and switch opening with reversed gate bias. You would first check for P or N polarity.
That's still a guess, but your considerations are incomplete without checking the most obvious explanation.
see this thread
https://www.edaboard.com/showthread.php?385762-IFC-TG179-TO-92-(transistor)&goto=newpost
i200yrs started it on July 14 2019
No, JFET is depletion mode FET, low resistance ("on") with zero gate voltage and off with reversed gate bias, positive voltage for PFET and negative voltage for NFET.On the other hand, do you agree that JFET 3 pins should be open to each other after discharge (discharge means by shorting all pins)? Because the original component maintain low-ohm (10ohms) even after discharged
No, JFET is depletion mode FET, low resistance ("on") with zero gate voltage and off with reversed gate bias, positive voltage for PFET and negative voltage for NFET.
There are FETs with different pin mapping available. Follow the suggestions in post #15 and consider all measurement information.